Crown hoist



4 Sheets-Sheet l L. E. ZERBE CROWN HOIST Filed Oct. 2, 1929 Dec. 19, 1933.

H In D L. E. ZERBE CROWN HOIS T Dec. 19, 1933 Filed Oct. 2, 1929 4 Sheets-Sheet 2 v "W ITR /I M 1 L AI M w 1. M E w 0 u 4 4 J 1 m I .M 1 u 9 l 6 w 4% i4 w E a H. m is 3 III w 7 a i .J 8 lwlb \\\mm? W 77 I a v :0 7 a J 2 n AA w w L. E. ZERBE GROWN HOIST Dec. 19, 1933.

Filed Oct. 2, 1929 4 Sheets-Sheet 3 mm? m 4 Dec. 19, 1933. 1.. E. ZERBE CROWN HOIST Filed Oct. 2, 1929 4 Sheets-Sheet 4 I or'ne J Patented Dec. 19, 1933 g UNITED STATES PATENT OFFICE CROWN HOIST Lewis E. Zerbe, Moneta,'Calii.

Application October 2, 1929. Serial No. 396,835

31 Claims. (Cl. 255-19) My invention pertains to a crown hoist and fluid of the crown hoist, which fluid may be conthe control mechanism therefor used in drilling trolled in its flow and therefore regulate the wells. descent of the string of drill pipe. In this con- My present invention may be considered an nection I utilize an, engine having preferably improvement on or for the development of my four cylinders, each having a reciprocating pispatent application Serial No. 248,912, filed Janton and the piston rods are all connected to a uary 23rd, 1928, for a crown hoist. common crank, therefore transmitting the power One of the objects of my invention is a crown to such crank. On the derrick floor or in any hoist for well drilling or other deep well operasuitable place I have hydraulic pumps, various 10 tions, in which in the drilling the progress or accumulators and tanks necessary to supply the rate of drilling may be governed by the weight hydraulic fluid for the engine and a control sysr oi' the drilling tool and string of drill pipe beartern. The control system may have a remote ing on the formation being out. control and reverse the valves of the engine in In this connection an object 01 my invention order to reverse the engine action.

16 is operating the crown hoist to lower the string A further object of my invention in a crown of drill pipe with the drilling cutter or bit in prohoist having an engine on the top of the derportion to the weight on the bit. Therefore rick, is the construction 01' the derrick together when the bit cuts the formation which is carried with the hoist whereby the engine may be eleaway by a hydraulic system, the drill string is vated through the derrick and lifted to the top 20 lowered, thus maintaining a substantial pressure thereof, whence it may be bodily placed in posiv on the bit. tion by structural members insertable to rest on In this connection a still further object of my the derrick and to support the weight of the invention is controlling the crown hoist and the engine. Thus the engine is hoisted as a unit drilling whereby when drilling through material and not piece by piece and assembled at the top 25 relatively easy to cut, the drilling may be comof the derrick.

paratively fast and when drilling through rela- Another objectof my invention is a crown tively hard material, the rate of cutting is rehoist in which a. heavy chain or the like is driven tarded, this being governed in both cases by the directly by a driving mechanism such as the weight on the bit. crank of the engine and this chain is arranged 80 A further object of my invention after the to act as either a hoist for a drill pipe or the like determination has been made of the correct on one of the falls while the other is descendweight or pressures to be used, is an automatic ing and then on the end which has descended to control of the crown hoist so that the drill raise other string 01' drill pipe or the like while string and bit is automatically lowered to mainthe first fall descends. 0r vice versa the chain 35 tain a substantially constant weight on the bit may be utilized with both falls to alternately ii and in which the rate of lowering of the bit lower the drill pipe or the like. Thus by my causes a relatively fast drilling through easy procedure one of the features of my invention drilling material and a slower rate of drilling eliminates the lowering or raising of an elevathrough hard material. In this connection I tor clevis or the like and the return of this to 40 may utilize the crown hoist to determine the its initial position before it can again do useful hydraulic pressure needed to suspend a certain work, length of drill P pe and when it is known the A further object of my invention is in a penproper number of stands which should have dulum type of device which may be operated their W ht carried by the bit, the control of to swing the two falls of 'the chain away from 45 the machine can be set so as to maintain the each other when one or these has a weight weight of the desired number of stands on the thereon; this action being automatic and due bit. to the fact that the chain fall having the heavy Another object of my invention is a hydrauliweight thereon is enabled to swing the pendually p ra d r wn h ist havin a hydraulic lum and thus shift the fall without any heavy 50 engine mounted on the top of the derrick, the weight to one side. The chain passes o engine being 01 Such character that it y be substantial sprocket wheel connected to the p itiv driv n by hydrau ic flui the w h crank driven by the engine, the falls pass over of the string of drill pipe acting on the engine idlers and are engaged by two idle sprockets may cause the operation of such engine, the mounted on a swinging pendulum.

5 engine therefore-in eflect pumping the hydraulic A further object o! my invention is in exerting a positive downward pull on a string of drill pipe or the like to overcome any upward thrust or blowing action due to gas pressures in the well acting to lift the string of drill pipe. By such construction I can prevent blowout of the drill tools and the like due to gas pressure or blowout gas. To obtain this result I have one fall of the hoisting chain connected in the usual manner to a string of drill pipe or the like and the other end adjustably connected to a cable which cable passes through a pulley block on or adjacent the derrick floor. The other end of the cable is attached to the string of drill pipe in such a manner to exert a downward pull thereon; this action being governed by the fact that one of the falls of the hoisting chain descends in lowering the drill pipe, the other end ascending and hence 'giving a pull on the cable.

An embodiment of my invention isillustrated in the accompanying drawings, in which,

Fig. 1 shows a view of my crown hoist and part of a derrick top taken in the direction of the arrow 1 of Fig. 2, with certain parts broken w y;

Fig. 2 is a view taken in the direction of the arrow 2 of Fig. lwith certain parts broken away;

3 is a vertical section taken substantially on the line 33 of Fig. 1 in the direction of the arrows, showing the cam shaft for operating the valves and the operating gears of such shaft;

Fig. 4 is a vertical section on the line 4--4 of Fig. 3, taken in the direction of the arrows, showing the valve housing partly broken away to illustrate a valve;

Fig. 5 is a detail section on the line 5--5 of Fig. 2 in the direction of the arrows, showing the automatic stop controlled by the chains at the end of its travel;

Fig. 6 is a vertical detail section on the line 6-601 Fig. 3, showing the valve control rack and pinion;

Fig. 7 is a detail section on the line 77 of Fig. 3, showing part of the stoppin and reversing lock mechanism for controlling the gears driving the cam shaft;

Figs. 8 and 9 are views similar to Fig. '7 in diflerent positions;

crown hoist;

Fig. 11 is a diagram of the piping and some of the control valves of Fig. on a larger scale;

Fig.- 12 is an elevational diagram showing a connection of the hoisting chains with a string of drill pipe to give a downward pull on such p p Fig. 13 is a diagram illustrating a connection for giving a downward pull on a well casing;

Fig. 14 is a section on the line 1414 of Fig. 3.

Figs. 15 and 16 are views of Fig. 5 taken in the direction of the arrow 15 and the section line 16-16 in the direction of the arrows respectively;

Fig. 17 is a diagrammatic perspective of the valve control for controlling the cylinder for reversing the engine valves.

The main fixed structural features of my inmention utilize a derrick designated generally by the numeral 11 which may be considered as having legs 12 and which derrick may be of more or less standard construction. It is provided at the top with transverse beams 13 connecting the legs and on the legs there are abutments 14. This construction leaves a large rectangular opening between the frame members 13 and the top of the legs.

An upper frame 15 comprises a series of posts 16 which are illustrated as resting on the abutments 14 and which are bolted or otherwise secured to the upper end of the derrick legs. This frame has a cap 17 formed of suitable connecting beams mounted on posts 16 and on this cap there are a set of nested sheaves 18 which may be utilized to hoist the engine and associated parts of the crown hoist through the opening 13 and place this on top of the derrick.

The crown hoist has a substantial engine bed frame 19 and on top of this there are nested sheaves 20. The cable for hoisting the engine is roved through the sheaves 18 and 20 and leads to a hoisting engine by which .the engine is elevated. On each side of the frame 19 there are extension plates 21 illustrated as having a dove-tailed recess 22 and in this recess is fitted transverse beams or plates 23 which rest on the legs of the derrick and also on the upper and end portions of the beams 13. When the engine frame is in position it may be securely bolted to the top of the derrick.

The hydraulic cylinder mounting ,utilizes hydraulic cylinders 24 of which in this construction I utilize 4. These cylinders are supported on the engine bed frame 19. It will be noted referring to Fig. 1, that the cylinders are arranged at an inclination to each other. By this construction the piston rods 25 operated by the pistons 26 converge downwardly. The cross heads 27 operate in guides 28 and connected to the cross heads there are connecting rods 29; these being attached to the cranks 30 on the hoist shaft 31. This hoist shaft is suitably journaled in the engine bed frame 19.

It will be noted, referring to Fig.2, that the connecting rods from each pair of cylinders are attached to the same crank and that each pair of cylinders is therefore connected to the crank at the ends of the hoist shaft. These cranks are arranged at 90 degrees one to the other. Such a construction causes the cylinders of each pair to be offset longitudinally of the hoist shaft relative to each other. The connecting rods and other shafts adjacent thereto are preferably mounted in a housing 32 connected to the engine bed frame 19.

The flexible hoisting gear designated generally by the numeral 33 utilizes a large sprocket gear 34 which is connectedto the hoist shaft 31 being clamped over the smaller sprocket and which sprocket has preferably three sprocket chains 35 passing thereover, these chains all being of the same pitch. Depending below the engine bed frame there is a gear casing 36 which has the idler gears 3'1 mounted therein on suitable stub shafts 38, these shafts being mounted in the gear case 36. The hoisting chains are fed over these idlers so that they are drawn close together and these are so located that the chain fall 39 utilized in drilling is centrally below the hoist shaft. The shifting pendulum 40 is mounted on a pivot pin 41 attached to the gear case 36 and this pendulum has two pendulum idler gears 42 suitably mounted and journaled thereon. These gears engage the inside faces of the hoisting chain, thereby holding the two ends of the chain spaced from each other. This pendulum and its idler gears 42 function to shift from side to side according to which drop of the chain has a weight thereon, such as the weight of the drill pipe for well casing, and thus shifts the idler end K away from the end carrying the load so that the load in one case is carried vertically below for are substantially as follows, having reference particularly to Figs. 1, 2, 3 and 4: The cam shaft housing 44 is mounted in the space between the double sets of cylinders and has a cam shaft 45 journaled therein and preferably mounted on anti-friction bearings. This shaft is illustrated as having four cams 46 which are arranged to actuate tappets 4'7 which operate the valves 48 through the medium of the valve stems 49. (Note particularly Fig. 4.) The valves bear on the seat 50 and the stems reciprocate to a bushing 51 formed in the valve guide 52 which forms part of the valve casing 44. This bushing is illustrated as having a socket 53 in which operatethe tappets 47. A suitable compression packing'54 engaging the stem and the bushing 51'forms a leak-proof joint. The valves are returned to their seat by a spring 55 hearing against the end of the valve 56 and the closure plug 57 on the outer end of the valve guidef Each of the cylinders is provided with a pair of intake and exhaust ports 58 at the top and also another set of intake and exhaust ports 59 at the bottom and there is suitable piping between the ports and the valve housing. The valvehousing contams four valves for each cylinder, each set of four being arranged to be operated by one of the cams 46. The cam shaft rotates so that the hydraulic fluid is fed to opposite ends of each cylinder and exhausted therefrom so as to give a continuous rotary motion to the main hoist shaft'in accordance with the direction of driving and the speed may be regulated and the drive automatically stopped as hereunder detailed. It is not believed necessary to describe in full the particular shape of the cams as these can be modified to obtain the desired opening and closing of the intake and exhaust valves at the upper and lower ends of each of the cylinders.

The drive for the cam shaft is by means of a cam driving shaft 60 which is vertically mounted and 'ournaled in a bracket 61 at the bottom and 62 at the top of the crank housing 32 (note Fig. 2). The bevel gear 63 is connected to the shaft 60 and is driven by a bevel gear 64, this latter being on a crank 65 connected to the cranks of the hoist shaft so that the gear 64 is concentric with such hoist shaft.

The upper part of the housing 32 on one side of the machine forms a case for enclosing the gears for operating the cam shaft. There is a gear driven shaft 66 which is journaled in a bracket 67 inside of the housing 32 and a bearing 68 on the side adjacent the cam shaft 45. A hub 69 is secured to the shaft 66 and there is a drive connection between the shaft 66 and the cam shaft 45. The vertical shaft 60 has a bevel gear '70'thereon which drives a crown gear '71 which crown gear is mounted on a hub '72 freely rotatable on the shaft 66 and forming downwardly by a spring 82.

part of a differential type of drive. The crown gear carries pinions '73 on pinion shafts '74 which pinions on one side mesh with a gear '75 which is keyed to the shaft 66 and on the other side engage a gear '76 which is freely rotatable on the shaft 66 (note Fig.3). This latter gear is used as a locking gear to cause the rotation of the shaft 66 and hence of the cam shaft in opposite directions through the medium-of the pinions and the gear '75. The gear '76 is provided with a peripheral flange '77, which flange has a surface '78 anda pair of diametrically opposite notches 79 (note Figs. '7, 8 and 9). A latching bolt 80 is slidably mounted in a bolt guide 81 (note Fig. 3), which bolt is urged The end of the bolt is adapted to engage in the notches '79 or to ride on the concentric surface '78. Positioned diametrically opposite and on one side of each of the notches there is a stop lug 81' limiting the motion of the gear 76 to a one-half turn when the lock bolt rides on the concentric surface '78.

A controlling cam 83 is rotatably mounted on the shaft 66 and extends over the hub portion 84 of the gear '76. This cam has a concentric portion 85 of a small radius and 86 of a large radius (note Figs. 3, '7, 8 and 9), with two cam sections 8'7 joining the concentric portions. The latch bolt is of sufficient width to overlap the cam and is raised by the cam sections 8'7 to ride on the section 86 which removes the lock bolt from the notches '79.

The manner of rotating the cam 83 is by means of a pinion 88 which is secured toa hub 11 section 89 of the cam 83 and this pinion meshes with a rack 90, such rack being vertically slidable and operating in guides and controlled by a valve controlled cylinder 91 having a piston therein 92 connected by a piston rod 93 with 1 5 the rack 90. By this means the rack 90 may move up or down and hence rotate the cam 83 in opposite directions. When the cam is in the position shown in Fig. '7, the gear '76 is locked from rotation and hence the drive to the shaft 66 is through the crown gear '71, the pinion '73, the gears 75 driving the shaft 66 and hence the cam shaft 45. This may -be presumed to be operating the cam shaft in such a direction that the fall of the hoisting chain which is in vertical alignment with the hoist shaft has a downward motion.

When the piston in the cylinder 91 is operated inthe manner hereinunder detailed, to reverse the raclr 90 the cam 83 is shifted to the no position shown in Fig. 8 which locks the gear '76 and hence the drive is to the shaft 66 but in an opposite direction. When the rack 90 operating through the pinion 88 shifts the cam 83 so that the bolt 80 rides on the peripheral surface 86 of the cam, the bolt 80 is removed from the notches '79 and hence the gear '76 may be driven a half turn in rotation. There is a slip action between the cam 83 and the gear '76 due to there being projections 92 on the hub 84 of the gear 4 engaging with projections 93 on the interior of the cam 83 (note Fig. 14).

The control of the cylinder 91 and hence of the cam shaft operating gears is as follows, having refence particularly to Figs. 1, 2 and 5: A rock shaft 94 is suitably mounted in journals 95 and 96 and on one end has a sheave 97 to which is attached a cable, this cable leading to the bottom of the derrick and passing over a control device operating on the principle of a mechanical telegraph control, that is shifting the cable one way rotates the rock shaft 94 in one direction and an opposite shift of the cable reverses the rotation of the shaft. Pivotally mounted on a bracket supporting the bearing 96 there are two arms 98 and 99 (note Fig. 5) and these connect to two vertical operating rods 100. These rods have a rack-and gear control of two valves 101, which valves regulate the flow of hydraulic fluid through the feed pipes 102 to the supply pipes 103 leading to the top and bottom of the control cylinder 91 (note Figs. 1 and 2).

The manner of operation of the arms 98 and 99 is by means of lugs 104, one of which is attached to each of the arms 99 and such lugs engage a cammed shoulder 105 in a cam 106, the cam being keyed to the shaft 94. Therefore'when the shaft 94 is rocked by rotating the shaftv9'1, by means of the cable, the rotation of the cam 106 causes the levers 98 and 99 to be rocked so that these are either spread apart or. drawn together, this being done through the reaction of the lugs 104 engaging the depression and the adjacent portions of the cam, such action through reversed racks operating the valves 101 to controlthe flow ofhydraulic fluid to the control cylinder 91. t

In order that there may be a positive stop in case the derrick man fails to stop or reverse the engine when the falls of the chain have arrived at the limit of their movement, I provide a stop lug 107 on the chain links in such a position that in the movement of the chain in opposite directions due to the medium of the hoist shaft and the large sprocket, such lug is brought into engagement with an arm' 108 which is keyed to the rock shaft 94. The operation of the lug 107 engaging this arm is to rock the shaft and hence shift the cam and the arms 98 and 99 into such a position that the engine is'reversed, this operating the cams. The control above mentioned for operating the hydraulic control cylinder'9l may be varied con-- siderably in the speed'of operation so that the rate at whichthe gear train'operating the cam shaft is changed, may also be considerably varied.

The hydraulic control for supplying fluid to the power cylinders is substantially as follows, having reference particularly to Figs. 10 and 11. In this construction there are illustrated two main supply pipes 108 and 109. The pipe 109 is shown as a supply pipe which leads from pumps or from accumulators supplied by pumps with hydraulic fluid under pressure. The pipe 108' is illustrated as a return pipe. In this return pipe there is a by-pass pipe 110 and on the pipe 108' and the by-pass there are two valves 1'11 and 112. These are interconnected by reverse racks 113 which may be manually operated in any suitable manner so that the movement of the rack in one direction opens one valve and closes the other, so that as the by-pass opens, the return flow through the main pipe is restricted. A pressure pipe 114 is illustrated as connected with the return pipe.

An automatic control of the return fluid which gives an automatic control of the descent of the drill pipe is as follows: A needle valve 115 is illustrated as having a seat 116, a guide 117 with suitable packing and a valve stem 118 with a needle connected thereto. This valve stem is connected through a variable fulcrumed lever 119 by means of the links 120. The other ,end of the lever is connected to a hydraulic pressure control device 121 which has a cylin- (note Fig. 1'1). In this cylinder there is a piston 123, this piston having a piston rod 124 and connected to the outer end of the lever 119 by means of a link 125. The lever has an elongated slot 126 therein which engages an adjustable fulcrum block 127 which is mounted on a stand 128 secured in a fixed or rigid position and being illustrated as attached to the pipe 108'. This stand has an elongated slot 129 in which the fulcrum block 127 operates. This block has a fulcrum pin 130 on which the fulcrum block 127 may rock, and this pin 130 is mounted in a slide block 131 which slides in the slot 129 of the stand 128 and is adjusted longitudinally of the slot 129 by means of the adjusting screw 132 which is threaded through the upper portion of the stand 128. A compression spring 133 is mounted in the cylinder 122, reacting against the pressure of the fluid.

The slot 129 has a slight downward slope towards the needle valve so that there is always assurance of a positive seat of the needle of the valve stem, no matter whether the lever 119 is adjusted 'for a long or a short fulcrum. This change of the fulcrum position is accomplished by adjusting the screw 132 and moving the fulcrum block longitudinally of the slot 129 in the stand 128 and hence the fulcrum block is shifted to different positions in the slot 126 of the lever 119.

By this interconnection of the .needle valve controlling the by-pass with a pressure device in the by-pass, it is possible to open and close the needle valve in accordance with the varying pressure in theby-pass and as the pressure increases the by-pass is opened, giving a freer flow and as the pressure decreases the by-pass tends to close; thus restricting the flow and thereby keeping a substantially constant relief pressure on the hoisting engines.

In order that a signal may be given indicating the operation of the needle valve, I provide a signal device indicated generally by the numeral 134. This has a fixed electrical contact 135 illustrated as mounted on the cylinder 122 and a movable contact 136 secured to the piston rod. The closing of these contacts operates to ring an electric bell 137 or give some other signal on closing of the circuit. As the by-pass is in the return pipe from the engines and the weight of the string of drill pipe causes a pressure on the outflow fluid from the engine, as the weight of the pipe is sufficient to operate the engine, thus communicating pressure to the pistons and to the hydraulic fluid. When the drilling tool rests on the bottom of the formation being cut, the pressure due to the weight of the drill pipe decreases and if the drill pipe were entirely supported on the formation, there would be substantially no pressure on the hydraulic fluid in the outlet or exhaust pipe from the engine. Therefore as the pressure decreases in the return pipe and in the by-pass, the bypass valve is gradually closed and this tends to build up the pressure in the return pipe as the drill is kept operated in cutting the formation and when a greater weight of the pipe is supported by the engine, the pressure in the by-pass pipe increases. Hence the needle valve is opened to relieve this increased pressure and allow downward feeding of the drill pipe. It is to be understood that the levers etc., for operating the der- 122 in communication with the by-pass 110 .of fluid to the control cylinder 91.

valves 111 and 112 are located in a convenient position for the drill man and preferably adjacent some place on the derrick floor.

In Fig. 10 I show part of a pipe and valves which may be used in connection with the hydraulic supply. An accumulator 138 is indicated as having pipes 139 and 140 which are connected to the downflow pipe 108' and the upfiow pipe 109 respectively. These are controlled by valves 141 and 142 which are preferably operated by a rack and lever construction. The accumulator may be also fed by a pump if desired. The pipes 108' and 109 are also connected to a source of fluid supply such as pumps or an accumulator fed by pumps which is not illustrated herein and these main flow pipes are controlled by valves 143 and 144. When the drilling is taking place and the string of drill pipe with the tool is suspended from the engine, the valves 143 and 144 may be closed and the valves 141 and 142 opened. Then the pressure on the fluid caused by the tendency for reverse action of the engine due to the weight of the tools, causes a flow of fluid through the pipes 108. and 109, 139 and 140 through the accumulator 138. Thus for controlling the gradual lowering of the string of drill pipes, it is not necessary to use the pumps in pumping the hydraulic fluid.

When drilling in a well having high gas pressure, there is sometimes a considerable force tending to raise the drill pipe and thereby preventing downward feed of the drill pipe and the drill bit. To overcome this objection I connect the opposite falls of the chain so that a direct downward pull may be exerted on the drill pipe. A construction suitable for this is illustrated in Fig. 12. In this drawing the clevis 43 on the fall 39 is illustrated as being connected to the ball of the spring hook 145 which is connected to the swivel 146. The other fall of the chain also has a clevis 147 which is indicated as attached to an elevator 148 having a special plug 149. To this plug there is connected a turnbuckle 150 and a cable 151 connects the turnbuckle and the swivel 146 passing through a snatch block 152 on or adjacent the derrick floor. A h0ok'153 is illustrated as attached to the swivel and to this one end of the cable is connected. By this means the drill pipe may have a downward pull exerted thereon on account of one end of the chain descending and the other end going up. When drilling under pressure it is necessary to have a stufling box 154 with flush joint couplings on the drill pipe as is the ordinary practice.

In Fig. 13 I show an arrangement for running drillpipe in or out of a hole in which a downward pull may be exerted. In this illustration a hook is illustrated as being connected to the elevator and the cable gives a downward pull on this hook; thus preventing a blowout of pipe.

In Figs. 5, 15 and 16 is illustrated the rock shaft control of the valve rods operating the valves 101 by means of the rods 100 and these lead to a rack construction indicated diagrammatically in Fig. 17 in which double racks 155 operate the two sets of valves for the control These are so arranged with the piping that when one of the rods lifts it will open the intake at the top of the cylinder 91 and open the exhaust at the bottom, thus allowing a downward movement of the piston in the cylinder. The other operating rod when shifted downwardly will open the exhaust top and inlet at the bottom of the cylinder 91, thus forcing the piston upwardly. It is manifest that if desired the arrangement inight be altered to suit any particular installa- In order to obtain a different gear ratio I have a smaller sprocket formed preferably as part of the crank shaft and over this the large sprocket wheel 34 which is formed in two sections which may be bolted together.

' The general manner of installing and operation of my invention is substantially as follows: As above mentioned as one of the features of my invention the crown hoist engine with its accessory devices may be hoisted to the top of the derrick by passing through the sheaves 18 and 20 and operating these by a hoisting engine of any suitable type; the posts 16 supporting the upper set of sheaves 18. When the engine as a whole is hoisted through the opening in the top of the derrick it may be secured in place by inserting the transverse beams or plates 23 and then by bolting or the like. For heavy lifting the small sprocket directly on the crank shaft may be used but for ordinary work the large sprockets are bolted over the small sprockets having the hoisting chains carried thereover. The engines are operated by hydraulic power in which the pumps and accumulators and the various controls are on or adjacent the derrick floor. As these pumps, etc., form no immediate part of this invention they are not set forth in full herein. The hydraulic fluid to operate the engine is conducted through pipes illustrated diagrammatically in Fig. 10 and the flow of the fluid is regulated by poppet valves as indicated in Fig. 4, such valves being operated by the cams shown particularly in Figs. 3 and 4. These cams are interconnected by the shaft 66 and 60 to be driven by the crank shaft and the gear ratio is such that the cam shaft rotates at the same speed as the crank shaft.

The cams may be reversed to reverse the engine by means of the cable passing over the sheave 97, which cable leads to the derrick floor or suitable location to control the engine. When the rock shaft 94 is rotated in one direction through the medium of telegraph cable, it operates the rock shaft which causes one cam 106 to move either up or down and in such action the cam operates on either of the lugs 104 and will either elevate one of the operating rods 100 or deposit the other rod and in such action controls the valves 101 which regulate the control cylinder 91 (note detail drawings in Figs. 5, 15, 16 and 17). In' Fig. 5 the operating rods 100 are illustrated in the neutral position so that all of the valves controlling the fluid to the cylinder 91 are closed.

The stoplug 107 adjacent opposite ends of the sprocket chain, is positioned to engage the arm 108 on either its downward or upward movement and hence the arm 108 causes the rocking of the rock shaft 94 and therefore the rotation of either of the cams 106, thus automatically moving the operating arms 100 controlling the valve 101 and thus the flow of hydraulic fluid to the control cylinder 91 and thereby reversing the engine.

When the piston in the cylinder 91 moves up and down it shifts the rack 90 which rack operates on the pinion 88 (note particularly Figs. 3, 6, 7, 8, 9 and 14). There is a lost motion between the operation of the pinion and the hub 84 of the gear 76 due to the spacing of the lugs 92 and 93 (note Fig. 14). This is sufiicient to allow lifting of the latching bolt -80 out of the retaining notches '79 and hence allow rotation of the gear 76. This gear operates the differential pinions 73 and thereby communicafes motion through the gear 75 to the shaft 66, hence rotating the valve cam a half circle to change the relation of the intake and exhaust ports of all of the cylinders. This action therefore reverses the operation of the engines and hence rotates the driving crank in the opposite direction.

The hoisting chains have their two depending ends guided by the idler sprockets 37 and it will be noted by reference to Fig. 1 that the fall of 7 one of the chains is substantially vertically below the center of the crank shaft. This would be the fall mostly used in drilling operations. The pendulum being allowed to shift freely from side to side through the idler gears 42 engaging the falls of the sprocket chain, causes the part of the chain which is operating late to shift sideways clear of the chain carrying a heavy weight and thus there is no danger of one chain following with the other on its up and down motion.

In order to obtain a value of the weight to be carried by the drilling tool, it is usually well known by the drillers how many stands of drill pipe should be used for particular types of bit and if desired when such a number of stands are being suspended by the chains, a reading may be obtained on the gauge 114 showing the hydraulic pressure corresponding to any definite number of drill pipes (note Fig. 10). When drilling operations are being carried on, the control valves for the flow of the hydraulic fluid through the pipes 108' and 109 is regulated so that the weight of the drill pipes operates the engine as a pump, pumping the fluid preferably in a continuous circle. The rack 113 is operated so as to control the valves 111 and 112 to shunt thehydraulic fluid through the by-pass pipe 110. The hydraulic pressure control device 121 is operated so that when the pressure in the pipe 110 increases, the lever 119 is forced up, thus lifting the-valve stem 118 and opening the valve in the by-pass; thus allowing a freer flow of the hydraulic fluid and a quicker descent of the tools. Therefore when the drilling becomes easy and the tools not being fed sufficiently fast to maintain a fast weight on the drill bit,thc pressure is built up in the engine due to an increased length of drill pipe being suspended and this increases the hydraulic pressure in the control device 121, thereby regulating the by-pass valve to give a freer flow and hence feed the string of drill pipe at a faster rate. Vice versa, if the pressure on the drill tool becomes greater than that desired as for instance due to hard drilling and greater weight of the drill string being supported on the bit, the hydraulic pressure of the pump in ,the engine is relieved and the automatic control 121 operates to decrease the opening of the by-pass valve and hence retract the flow of fluid from the engine, thereby retarding the descent of the drilling string until a proper weight bears on the drill tools.

The length of the effective fulcrum of the lever 119 is obtained by the adjusting screw 132 (note Fig. 11) and it will be noted that the fulcrum block 127 rides in a slight incline so that the valve stem 118 can always be brought to bear on its seat 116. It willtherefore be seen that by this automatic control I may maintain a substantially constant predetermined pressure or weight on the drill bits.

The construction of Figs. 12 and 13, by having the cable 151 leading downwardly from one of the falls of the hoisting chain and connected through a snatch block secured in a solid position to the ground and with the free end connected to a string of drill pipe or the like, allows a constant downward tension to be exerted and thus prevents the danger of blow out of the drill pipe.

While I have illustrated my invention as using hoisting chains operating over sprockets, it is to be understood that any suitable type of flexible hoisting arrangement may be utilized, whether this is by cables running over drums or any other suitable construction.

A characteristic feature of my invention is that my appliance has absolute control of the rate at which the drilling bit descends in the operation of the well drilling and should the formation become hard and the drilling difficult the rate of descent is retarded but the drilling tool still continues downwardly. In this respect ,my invention distinguishes from other devices in which when the drilling tool encounters hard work, such as in a hard formation, the tool is raised off the bottom or if not actually raised the pressure on the bit is lessened by a tension being exerted on the drill pipe. One of the difficulties of this latter procedure is that injury to the bit is done quickly and is frequently done before the pressure is relieved, whereas with my construction and means of control the slowing of the descending movement of the bit in drilling is immediately retarded when the bit enters and strikes a hard formation so that the damage to the bit is not done by having a heavy pressure on the bit working in a hard formation.

The cable 151 which connects to the free end of the hoist chain and also to the drill pipe suspended from the opposite end of this chain operates as a safety factor, for when the weight of the pipe is so light that gas pressure in the well could force this pipe up, the cable 151 functions to prevent such blowout and may be utilized with the control of the main driving shaft and,the sprocket 34 to allow the gas pressure to force the pipe upwardly in a slow manner. Therefore, the main shaft 31 may be rotated in one direction by the weight of the drill pipe on the suspending end of the chain and may be rotated in the opposite direction when the gas has sufficient force to lift the drill pipe in the well.

Various changes may be made in the prin ciples of my invention without departing from the spirit thereof as set forth in the description, drawings and claims.

I claim:

1. In a drilling apparatus having a hydraulic engine to raise and lower drill pipe, a pipe leading from said engine to carry the return flow of hydraulic fluid only and having a by-pass, a hydraulic pressure device connected in said by-pass, a lever connected to said pressure device, a valve in the by-pass having a valve stem connected to the lever, whereby the opening and closing of the-valve is regulated by the said pressure device.

2. In a drilling apparatus as claimed in claim 1, the lever having an adjustable fulcrum and I said fulcrum operating on an incline to adjust the valve stem to always close when the pres- .sure device indicates a low pressure.

3. In a drilling apparatus, an engine having a plurality of cylinders, each with a piston and adapted to be mounted on top of a derrick, a common crank driven by the piston rods, a flexible hoisting member operated by the said crank, the said hoisting member having two ends, either of which may be used to hoist or lower drilling tools or the like.

4. In a drilling apparatus a rotatably mounted main shaft, means for rotating the shaft forward or in a reverse direction and means to prevent rotation of the shaft, a first flexible member operatively connected to the shaft to be driven thereby, said flexible member having two depending ends, with means for attaching a load to such ends, and a second flexible member connecting said ends whereby the said flrst flexible member and the said flexible connecting means may operate as an endless flexible member, there being in addition an upper pair of fixed guides and a lower pair of guides on the first flexible member each with a guide means and located below the main shaft, means to shift the lower pair of guides to divert the depending ends of the flrst flexible member whereby the end carrying a load may be substantially directly below the said main shaft.

5. In a drilling apparatus a main shaft, a flexible load supporting member depending from said shaft and having two ends on opposite sides thereof each with a load supporting means, means to rotate the shaft or said shaft being rotatable by a load on one end of the flexible member, means for automatically or manually controlling the forward or reverse rotation of said shaft and means for positively preventing such rotation, and a shiftable guide means positioned below the shaft and engaging the flexible member to shift the depending ends laterally whereby the end carrying a load depends substantially vertically below the said shaft.

6. In a drilling apparatus as claimed in claim 5, the shiftable guide means having a first pair of rotatable wheels engaging depending portions of the flexible member, and a second pair of shiftable wheels each engaging the flexible member below the first pair of wheels, the second pair of wheels diverting the depending ends of the flexible member laterally.

7 In a device as described, the combination of a well derrick, an engine having a crank shaft and a sprocket. driven by the crank shaft mounted on the top of the derrick, said sprocket beingover the well hole and axially centered over the derrick, a'sprocket chain fitting over said sprocket and having two depending ends, 7

each end having means for engaging drilling tools or'the like, and means to operate said engine whereby one of the ends may ascend while the other is descending.

8. In a device as described in claim 7, a shiftable guiding means for the depending ends of the chain, said means being operated by the depending portion of a chain having a load thereon to shift such end having the load into substantial axial alignment with the load.

9. In a device as described, the combination of a well derrick having an engine with a crank andva sprocket wheel mounted thereon, a chain fitting over said sprocket and having two depending ends, each end having means for supporting a load, fixed guides for the depending ends of the chain to locate both ends of the chain substantially vertically over the load to be carried by each end, and a shiftable guide means actuated by the end of the chain having a load thereon to shift the end without a load laterally clear of the end carrying a load.

10. In a device as described, a well derrick having an engine mounted on the top thereof, a drive means operated by such engine, a flexible load supporting means mounted on the drive means and actuated thereby and having two depending ends extending downwardly in the derrick, a fixed guide means for said depending ends to locate said ends substantially vertically over the load to be carried by each end, and ashiftable guide engaging both of the ends and shifted by the end having a load thereon to move the other end out of axial alignment with the load.

11. In a device as described in claim 10, the fixed guide means comprising rollers mounted on fixed axes, and the shifting guide means comprising a pendulum, the pendulum having guide rollers thereon to engage said depending ends and to be operated by the end carrying the load to shift the end without a load.

12. In a device as described, a well derrick having an engine mounted on the top thereof, a shaft driven by the engine and a sprocket wheel mounted on the shaft, a sprocket chain fitted 1- over the sprocket and having two depending ends, a pair of guide idler sprockets rotatably mounted on fixed axes below the sprocket wheel and engaging the depending ends of the sprocket chain on their outside surface, such ends being brought into close proximity and substantially axially over the load in the center of tho derrick, a pendulum pivoted below the shaft and having a pair of guide sprockets mounted on opposite sides of the pendulum and positioned to engage the inside of the chain, the pendulum being operated by the depending end having a load thereon to shift the end having no load out of axial alignment with the center of the derrick. 13. In a device as described in claim 12, a flexible cable, a pulley mounted on the floor of the derrick, a hold down cable having a connection to the depending end of the chain without the load and having a connection to the upper end of the load being carried by the load carrying end' of the chain, said cable passing over said pulley.

14. In a drilling apparatus, a well derrick, a power driven rotatable shaft at the top of the derrick, a flexible hoisting and lowering element operated by said shaft and having two ends depending within the derrick, both being adapted to raise and lower tools and the like, a load carried by one end, the other end being without a load, a pulley attached to the derrick floor, and a fixed hold down cable having a connection to the load and to the end without a load and passing over said pulley.

15. In a drilling apparatus, a well derrick, a

power driven rotatable shaft at the top of the to the load and to the end without a load, a

pulley secured to the derrick floor over which said cable passes, and means to shift the depending end of the chain without the load when the weight of the load is borne by the other end to 159 prevent interference between such unloaded end and the end carrying the load.

16. In a drilling apparatus, a hydraulic engine having means to raise and lower drill pipe, means to supply a hydraulic fluid to such engine, a return pipe from the engine having a by-pass therein, a hydraulic pressure device connected in said by-pass, a valve also in the by-pass, said valve being controllable by the hydraulic pressure device to regulate the return flow of the hydraulic liquid through the by-pass, and additional valves controlling the flow of hydraulic liquid through said return pipe.

17. In a drilling apparatus, a hydraulic engine having means to raise and lower drill pipe, a supply connection for such engine, a return pipe leading from the engine for the hydraulic fluid and having a by-pass therein, valves in the return pipe and in the by-pass, means to reciprocally operate said valves, said by-pass having a hydraulic pressure device, .a lever connected to said pressure device, a valve in the by-pass having a valve stem connected to the lever whereby the flow of hydraulic fluid through the by-pass is regulated by said pressure device.

18. In a drilling apparatus, the combination of a well derrick, a hydraulic engine mounted at the top of such derrick and operating a drive means with a drive mechanism, a flexible suspension means actuated by said mechanism and being adapted to suspend, raise, and lower drill pipe, a feed and a return pipe to and from the engine, the return pipe from the engine having a by-pass, a. valve in the return pipe and in the bypass, interconnecting means to reciprocally operate said valves, a hydraulic pressure device in the by-pass, a lever operatively connected thereto, such lever having an adjustable fulcrum mounted in a guideway, a second valve in the by-pass having a connection to said lever, such latter valve additionally regulating the flow of hydraulic fluid through the by-pass.

19. In a well drilling apparatus, a well derrick having a rotatably mounted shaft at the top of the derrick, a first flexible member operatively connected to the shaft to be driven thereby and having two depending ends, each with means to attach a load, a load connected to one of such ends, a second flexible member having one end connected to the load and the other end connected to the free end of the first member, a pulley adjacent the derrick floor forming a lead for the second flexible member, a power means to rotate said shaft in either direction, said power means permitting said shaft to be rotated by the weight of the load attached to one end of the first flexible member. 7

20. In a well drilling apparatus as claimed in claim 19, a flexible guide means positioned below said shaft and engaging both ends of the first flexible member, said guide means being shiftedby such member due to the weight of the load attached to one end thereof to permit the load to hang substantially vertically below said shaft.

21. In a drilling apparatus, a power driven rotatably mounted main shaft with means power operated to rotate said shaft in a forward or a reverse direction, and means to prevent rotation of the shaft, a first flexible membenoperatively connected to the shaft to be driven thereby and having two depending ends, with means for attaching a load to each end, a load suspended from one end of said flexiblemember, a second flexible member having one end detachably connected to the load and the other end detachably connected to the free end of the first flexible member, a pulley forming a guide for the second flexible member, the weight of the load being adapted to cause rotation of said shaft and movement of the two flexible members, or the load being adapted to be moved downwardly by rotating the shaft and exerting a tension on the second flexible member attached to the free end of the first flexible member, or said shaft being adapted to be rotated by an upward lift on the load, the tension on the second flexible member pulling down on the free end of the first member.

22. In a well drilling apparatus, a derrick having a rotatable shaft mounted at the top, a flexible member operatively connected to said shaft to be driven thereby and having two depending ends, each with means to support a load, a power means to rotate said shaft in a forward or reverse direction, an automatic means controlled by the flexible member to reverse the direction of rotation, said power means being adapted to permit rotation of the shaft by the weight of the load carried ,by the flexible member, and said shaft being rotated in reverse directions by attaching the load to the different ends of the flexible member.

23. In a well drilling apparatus, a well derrick, a rotatably mounted shaft at the top of the derrick, a first flexible member connected to said shaft to be driven thereby and having two depending ends, means for attaching a load to one end, a second flexible member connected to the end of the first flexible member having the load and having another end connected to the free end of the flrst flexible member, a guide pulley adjacent the derrick floor for the second flexible member, a power means to rotate said shaft in a forward or reverse direction whereby the load may be elevated by power or pushed down by power against a resisting pressure, means for positively preventing rotation of the shaft, said shaft being rotatable by the weight of the load on the first flexible member, or said shaft being rotatable in a reverse direction by an upward lift on such load due to a lifting pressure on the load, and means to control the rotation of the shaft when actuated by the weight of the load or an upward lift on the load.

24. In a well drilling apparatus as claimed in claim 23, the power means to rotate the shaft comprising a hydraulic engine, a control for said engine for lowering the load uninterruptedly and continuously at various speeds without lifting by controlling the flow of the hydraulic fluid through said engine.

25. In a drilling apparatus, a main shaft mounted for forward or reverse rotation, a flexible member operatively connected to the shaft and having two depending ends with means to support a load at either end, means to positively drive the shaft in either direction, a

manual control means for changing the direction of rotation of the shaft, an automatic means actuated by the flexible member when one of the ends is adjacent the shaft "to change the direction of rotation, means for automatically or manually controlling the speed of rotation of the shaft when a load is being lowered, the direction of rotation of the shaft being reversible by shifting the load from one end of the flexible member to the other end, the load on said flexible member being adapted to rotate said shaft, and means for positively preventing the rotation of the shaft.

26. In a crown hoist, a well derrick having an opening at the top, an upper frame secured to the derrick and extending above the top and having sheaves at the top of said frame, an

1 engine bed frame having traveling sheaves secured thereto, and an engine mounted in said frame, said engine having means for raising and lowering drill pipe, said sheaves being adapted for the roving of a cable for hoisting the engine bed frame and the engine upwardly through the derrick and'partly through the opening in the top, and insertable beams to engage the top of the derrick and part of the engine bed frame to support the engine bed frame on top of the derrick.

27. In a crown hoist as claimed in claim 26, said engines having cylinders with reciprocating pistons therein, the means for raising and lowering the drill pipe comprising a crank shaft with a sprocket wheel thereon, and a hoisting and lifting chain extending over the sprocket wheel, said chain having means at each end for engaging the drill pipe.

28. In a crown hoist, a well derrick having an opening at the top, an upper frame connected to the upper portion of the derrick extending above the top with a set of stationary sheaves at the top of said frame, an engine bed frame having an engine therein with a rotatable shaft, said bed frame having traveling sheaves, said sets of sheaves being adapted for the 'roving of a cable to hoist the engine bed frame with the engine upwardly through the derrick and partly through the opening in the top, the engine bed frame having outwardly extending extension plates and insertable beams to engage said plates and rest on top of the derrick to support the engine bed frame and the engine or: the top of the derrick after removal of the cable.

29. In a crown hoist, a well derrick having an opening at the top, an upper frame secured to the derrick and extending above the top thereof, the upper frame having a set of stationary sheaves, an engine bed frame having a set of traveling sheaves, said sheaves being adapted for the roving of a hoisting cable, the engine bed frame having a rotatable shaft adapted for a power drive to rotate same and for raising and lowering drill pipe, an insertable beam to rest on the top of the derrick and engage the engine bed frame to support said frame at the top of the derrick after removal of the hoisting cable.

30. In a well drilling apparatus, a hydraulic cylinder having a reciprocating piston therein, a shaft, a driving connection from the piston to the shaft, a drill string having a drill tool, means to suspend the string from the shaft, a hydraulic supply pipe to the cylinder, a discharge pipe from the cylinder, a control means in the discharge pipe, a regulating device for said control means operated by the suspended weight of the drill string, whereby the downward speed of the drill string may be increased when the supported weight decreases by increasing the flow through the discharge pipe, and conversely by decreasing the flow through the discharge pipe when the supported weight increases the downward movement of the drill string may be decreased.

31. In a well drilling apparatus, a hydraulic cylinder having a reciprocating piston therein, a shaft, a driving connection from the piston to the shaft, a drill string having a drill tool, means to suspend the string from the shaft, a hydraulic supply pipe to the cylinder, a discharge pipe from the cylinder, 9. control means in the discharge pipe, a regulating means operative to determine the pressure on the tool and 110 to decrease the flow through the discharge pipe when the weight on the tool increases and thereby decrease the rate of lowering of, the drill string, and conversely to increase the discharge from the discharge pipe when the weight 115 on the tool decreases and thereby increase the speed of lowering of the drill string.

LEWIS E. ZERBE. 

